For reference, I just committed the fix, see message below. Thanks to all who helped out.
> CVSROOT: /cvs > Module name: src > Changes by: an...@cvs.openbsd.org 2017/06/25 02:51:53 > > Modified files: > bin/ksh : emacs.c > > Log message: > Don't output partial UTF-8 characters in ksh emacs mode. Instead, try to read > a > complete UTF-8 character first. Fixes an issue while running ksh in tmux where > UTF-8 characters inserted in columns other than the last one are discarded. > > With help from nicm@ and schwarze@ who also wrote the UTF-8 validation, > thanks! > > ok schwarze@
